A Third Massive Star Component in the sigma Orionis AB System

Simón-Díaz, S.(1,2); Caballero, J. A.(3); Lorenzo, J.(4)

(1) Instituto de Astrofísica de Canarias
(2) Departamento de Astrofísica, Universidad de La Laguna
(3) Centro de Astrobiología (CSIC-INTA)
(4) Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Universidad de Alicante

We report on the detection of a third massive star component in the σ Orionis AB system, traditionally considered as a binary system. The system has been monitored by the IACOB Spectroscopic Survey of Northern Massive Stars program, obtaining 23 high-resolution FIES@NOT spectra with a time span of ~2.5 years. The analysis of the radial velocity curves of the two spectroscopic components observed in the spectra has allowed us to obtain the orbital parameters of the system, resulting in a high eccentric orbit (e ~ 0.78) with an orbital period of 143.5 ± 0.5 days. This result implies the actual presence of three stars in the σ Orionis AB system when combined with previous results obtained from the study of the astrometric orbit (with an estimated period of ~157 years).

Reference: 2011, ApJ, 742, 55S
Status: Manuscript has been accepted

Weblink: http://adsabs.harvard.edu/abs/2011ApJ...742...55S


Email: ssimon@iac.es